Conventional steam stripper ammonia abatement cycles suffer from a number of deficiencies. These deficiencies include, for example, relatively high energy requirements, slow reaction kinetics, and large absorber requirements to name just a few. It would be advantageous if new systems and methods could be developed which required less energy, had faster reaction kinetics, and smaller absorber requirements. The embodiments described herein solve many of the aforementioned deficiencies and offer their own advantages as well.
In one embodiment the invention pertains to a process for separating or recovering basic gases comprising first absorbing ammonia from an ammonia containing gas stream into an ammonia-lean solution, forming an ammonia-rich solution. The ammonia rich solution is enriched with one or more acid gases. One or more ammonia-acid gas salts are precipitated before enriching, during enriching, after enriching, or a combination thereof. In a second embodiment the invention pertains to a process for separating or recovering basic gases comprising first absorbing ammonia from an ammonia containing gas stream into an ammonia-lean, an ammonia-ultra-lean, or ammonia-free solution, to form an ammonia-rich solution. The ammonia-rich solution is enriched with one or more acid gases to form an ammonia-rich, acid gas rich solution. The ammonia-rich, acid gas rich solution is concentrated using one or more membranes to form a retentate and a permeate. The permeate is suitable for use as at least a portion of the ammonia-ultra-lean or ammonia-free solution.
A third embodiment pertains to an integrated process for separating or recovering basic gases comprising a first cycle and a second cycle. The first cycle comprised absorbing ammonia from an ammonia containing gas stream into an ammonia-lean solution, forming an ammonia-rich solution; enriching said ammonia rich solution with one or more acid gases; precipitating one or more ammonia-acid gas salts wherein said precipitating occurs before enriching, during enriching, after enriching, or a combination thereof; and separating said precipitate from any remaining liquid. The second cycle comprises (a) absorbing ammonia from an ammonia containing gas stream into an ammonia-lean, an ammonia-ultra-lean, or ammonia-free solution, to form an ammonia-rich solution; (b) enriching said ammonia-rich solution with one or more acid gases to form an ammonia-rich, acid gas rich solution; and (c) concentrating said ammonia-rich, acid gas rich solution using one or more membranes to form a retentate and a permeate wherein said permeate is suitable for use as at least a portion of the ammonia-ultra-lean or ammonia-free solution in step (a) of the second cycle.